3 Significant ways for DC motor speed control One of the most useful features of DC motor control is the speed control. If you control the speeds of the motor, you need to vary the speed of the motor according to the requirements for getting the required operation. There are many applications like the movement of the robotic vehicles, motors in paper mills, and elevators use the speed control mechanism.
DC Motor’s working principle When a conductor carrying current is placed in a magnetic field it is controlled by a mechanical force and this is the simple working of the DC motor. The current carrying conductor and the field is the armature in a DC motor. The magnetic flux is produced on its own with a supply of the current to the conductor (armature). Due to field windings it either adds up to the magnetic flux at one direction or rejects the magnetic flux due to field windings. The rotation is because of the accumulation of magnetic flux at one direction compared to the other. Faraday’s law of electromagnetic induction shows that the rotating action of the conductor generates an EMF. The supplied voltage or the cause is opposed by the EMF according to Lenz’ law. In case of varying load due to the EMF, the torque is adjusted and this is the speciality of DC motor.
3 ways of controlling DC motor speed control 1 Flux Control Method The magnetic flux of the winding is varied for varying the speed of the motor. By changing the current flowing through the field windings the magnetic flux can be changed as it depends on the current flowing through the windings. This is achievable with the help of a variable resistor in a series with the field winding resistor. The variable resistor kept at the minimum position flows through the windings due to the speed voltage keeps the speed normal. The current through the field winding is reduced when the resistance increases slowly. Thus the flux voltage produced is reduced in turn. Beyond a particular normal value the speed of the motor increases.